I. Field of the Invention
The present invention relates to devices used in producing a skin incision for the purposes of obtaining a blood sample from a patient. More particularly, the present invention relates to disposable, one-time-use lancet devices that extend a blade from a protective housing and retract the blade back into the housing after the incision has been made.
II. Prior Art Statement
Blood samples are routinely drawn from a patient for use in various types of blood tests. The blood is usually taken from an appropriate area, such as the patient's fingertip. A series of mechanical devices for producing skin incisions necessary to draw blood samples have been developed. One such device is a reusable mechanical device that has a disposable blade. To its advantage, the mechanical device prevents the patient from seeing the often unsettling scene of his skin being cut. Further, the mechanical device provides good control of the incision. However, handling of the blades during disposal presents a danger. There is the danger of being cut by the exposed edge. Further, the health problems posed by used blades are apparent. More recent health considerations, including the possibility of contracting the AIDS virus from disposed blades, have increased the need for safer devices.
Recognizing the dangers presented by used lancet devices, numerous prior art devices have been developed that automatically retract a blade into a safety housing after the incision is made. This prevents further contact with the blade and eliminates the problem of the blade accidentally cutting another. Such prior art devices therefore typically include a cutting blade, a safety housing, a means to project the cutting blade out of the housing, a means to retract the blade back into the housing and a triggering device. Accordingly, such prior art lancet devices tend to have complex workings that are expensive to manufacture, difficult to assemble and are hard to use. Examples of such prior art are shown by U.S. Pat. No. 3,760,809 to Campbell, entitled SURGICAL LANCET HAVING CASING; U.S. Pat. No. 4,064,871 to Reno, entitled DEVICE FOR MAKING PRECISE INCISIONS FOR BLEEDING TIME TESTING AND THE LIKE; and U.S. Pat. No. 4,157,086 to Maiorano et al, entitled APPARATUS FOR PROVIDING SKIN CUTS TO A PREDETERMINED MEASURE.
Since one-time-use lancet devices are designed to be disposable after one use, it will be understood that the manufacturer with the lowest unit price would have an advantage over competitors. Consequently, manufactures have been motivated to design disposable lancets with simpler designs that can be made less expensively. In response to such design efforts, manufactures have developed lancets with only two or three separate parts. In such devices a cutting blade is held by a complex molded structure that both advances and retracts the blade. Such prior art is exemplified by U.S. Pat. No. 4,553,541 to Burns, entitled AUTOMATIC RETRACTABLE LANCET ASSEMBLY, and U.S. Pat. No. 5,212,879 to Biro et al., entitled METHOD FOR MANUFACTURING A DISPOSABLE-RETRACTABLE FINGER STICK DEVICE, which is assigned to International Technidyne Corp, the assignee herein. Although such devices have far less parts than some prior art lancet devices, they are no less complex. Accordingly, the tools needed to mold the primary lancet structure is highly complex and the parts produced must be maintained at high tolerances. This produces a large amount of reject parts and significant downtime as the molding tool is cleaned and maintained. All this work adds to the cost of the lancet device and makes it difficult to consistently produce a high quality product.
It is therefore an object of the present invention to provide a disposable lancet that is relatively inexpensive to manufacture and not requiring complex molded parts.
It is a further object of the present invention to provide a disposable lancet that is easy to use and highly consistent in its operation.